Process for hydrotreating residual petroleum oil

ABSTRACT

A method for hydrotreating residual oil which comprises utilizing a hydrotreating catalyst which contains a thermally stable composition comprising a layered metal oxide containing an interspathic polymeric oxide having a d-spacing of at least about 10 angstroms at hydrotreating conditions. Said conditions include temperature ranging from about 357° C. to 454° C. (675° F. to 850° F.), a hydrogen partial pressure of at least about 2860 kPa (400 psig) and a liquid hourly space velocity ranging between about 0.1 and 10 hr -1 .

This is a continuation of U.S. Ser. No. 774,520 filed Sept. 10, 1985,now U.S. Pat. No. 4,600,503 which is a continuation-in-part of U.S. Ser.No. 687,414 filed Dec. 28, 1984, and now abandoned, the entire contentsof which are incorporated hereby by reference.

This invention relates to a process of upgrading residual petroleum oilsby hydrotreating. More particularly, the present invention relates tohydrotreating residual petroleum in the presence of a catalystcomprising a layered metal oxide component containing an interspathicpolymeric oxide. This invention also relates to catalysts forhydrotreating residual petroleum oil, as well as methods of making thecatalyst.

Residual petroleum oil fractions such as those heavy fractions producedby atmospheric and vacuum crude distillation columns, are typicallycharacterized as being undesirable as feedstocks for most refiningprocesses due primarily to their high metals, nitrogen, Conradson carbonresidue and/or sulfur content. The presence of high concentrations ofmetals and sulfur and their compounds preclude the effective use of suchresidua as chargestocks for cracking, hydrocracking and cokingoperations as well as limiting the extent to which such residua could beused as fuel oil. Perhaps the single most undesirable characteristic ofsuch feedstocks is their high metals content. Principal metalcontaminants are nickel and vanadium. Sulfur is also undesirable in aprocess unit chargestock. The sulfur contributes to corrosion of theunit mechanical equipment and creates difficulties in treating productsand flue gases. At typical cracking conversion rates, about one-half ofthe sulfur charged to the unit is converted to H₂ S gas which must beremoved from the light gas product.

Increasingly, residual oil is being upgraded into lighter petroleumproducts, notably transportation fuels, by hydrotreating the residualoil. This treating of residual oil in the presence of a catalyst andhydrogen to transform it into lighter petroleum products is difficultbecause of the aforementioned presence of sulfur, nickel and vanadium inthe molecules of the residual oil.

Catalysts having different size pores have been used to hydrotreatresidual oil. For example, it has been recognized that large porecatalysts remove metals faster than small pore catalysts whereas smallpore catalysts remove sulfur faster than large pores.

In the prior art, several catalysts, each having individual porecharacteristics, have been employed to hydrotreat residual oils. Forexample, U.S. Pat. No. 4,054,508, teaches a process whereby a resid ispassed over a large pore catalyst in order to demetallize the residwhich is thereafter passed over a small pore desulfurizing catalyst.U.S. Pat. No. 4,267,071 teaches a hydrotreating catalyst whose pore sizedistribution is specifically tailored to complement the particular residfeed to be processed.

U.S. Pat. No. 4,389,304 discloses a hydrodesulfurization orhydrodenitrogenation catalyst containing alumina loaded with cobalt,molybdenum and titanium, while U.S. Pat. No. 4,287,050 discloseshydrodesulfurization with alumina promoted with zinc titanate, cobaltand molybdenum.

U.S. Pat. No. 3,865,895 discloses the use of layered complex metalsilicates such as chrysotile in processes such as hydrodesulfurizationand hydrodenitrogenation. However, the interlayer separation isrelatively small for demetallation as is evidenced by d-spacings nogreater that about 7.9 angstroms.

Because the principal metal contaminants such as nickel, vanadium, ironand copper are often associated with large planar organometalliccomplexes such as metalloporphyrins and similar cyclic tetrapyrroles, inthe asphaltene fractions of resids, it would be particularlyadvantageous to employ a hydrotreating catalyst highly selective towardsthese shapes in resid upgrading. Such a material should exhibit not onlyhydrogenation activity, but also thermal stability such that thecatalyst is capable of withstanding conditions ordinarily encounteredduring hydrotreating.

It has now been found that thermally stable layered metal oxidescontaining interspathic polymeric oxides may be employed inhydrotreating catalysts used to upgrade residual oil. Preferably, ahydrogenation component comprising metals selected from the groupconsisting of Group VIB and Group VIII is incorporated in thehydrotreating catalyst. The catalyst enhances removal of undesirablemetals, sulfur, nitrogen and Conradson carbon residue.

Many layered materials are known which have three-dimensional structureswhich exhibit their strongest chemical bonding in only two dimensions.In such materials, the stronger chemical bonds are formed intwo-dimensional planes and a three-dimensional solid is formed bystacking such planes on top of each other. However, the interactionsbetween the planes are weaker than the chemical bonds holding anindividual plane together. The weaker bonds generally arise frominterlayer attractions such as Van der Waals forces, electrostaticinteractions, and hydrogen bonding. In those situations where thelayered structure has electronically neutral sheets interacting witheach other solely through Van der Waals forces, a high degree oflubricity is manifested as the planes slide across each other withoutencountering the energy barriers that arise with strong interlayerbonding. Graphite is an example of such a material. The silicate layersof a number of clay materials are held together by electrostaticattraction mediated by ions located between the layers. In addition,hydrogen bonding interactions can occur directly between complementarysites on adjacent layers, or can be mediated by interlamellar bridgingmolecules.

Laminated materials such as clays may be modified to increase theirsurface area. In particular, the interlamellar spacing can be increasedsubstantially by absorption of various swelling agents such as water,ethylene glycol, amines, ketones, etc., which enter the interlamellarspace and push the layers apart. However, the interlamellar spaces ofsuch layered materials tend to collapse when the molecules occupying thespace are removed, for example, by exposing the clays to hightemperatures. Accordingly, such layered materials having enhancedsurface area are not suited for use in chemical proceses involving evenmoderately severe conditions.

The extent of interlayer separation can be estimated by using standardtechniques such as X-ray diffraction to determine the basal spacing,also known as "repeat distance" or "d-spacing." These values indicatethe distance between, for example, the uppermost margin of one layerwith the uppermost margin of its adjoining layer. If the layer thicknessis known, the interlayer spacing can be determined by subtracting thelayer thickness from the basal spacing.

The method of the present invention may utilize a hydrotreating catalystprepared from a layered oxide starting material which contains ionexchange sites having interspathic cations associated therewith. Suchinterspathic cations may include hydrogen ion, hydronium ion and alkalimetal cation. The starting material is treated with a "propping" agentcomprising a source of organic cation such as organoammonium ion inorder to effect an exchange of the interspathic cations resulting in thelayers of the starting material being propped apart. The source oforganic cation in those instances where the interspathic cations includehydrogen or hydronium ions may include a neutral compound such asorganic amine which is converted to a cationic analogue under suchconditions. The organic cation should be capable of displacing orsupplanting the original interspathic cations. The foregoing treatmentresults in the formation of a layered metal oxide of enhanced interlayerseparation depending upon the size of the organic cation introduced.

After the ion exchange, the organic-"propped" species is treated with acompound capable of forming the above-described polymeric oxide.Preferably, such compounds are capable of forming the polymeric oxideupon hydrolysis. It is preferred that the organic cation depositedbetween the layers be capable of being removed from the layered oxidematerial without substantial disturbance or removal of the interspathicpolymeric oxide. For example, organic cations such as n-octylammoniummay be removed by exposure to calcination or chemical oxidationconditions, preferably after the interspathic polymeric oxide precursorhas been converted to the polymeric oxide.

The polymeric oxide precursor-containing product is exposed to suitableconversion conditions, such as hydrolysis and/or calcination to form thelayered material employed in the present invention. The hydrolysis stepmay be carried out by any method, for example, by interspathic wateralready present in organic-"propped" layered oxide material. Because ofthe effect of interspathic water on hydrolysis, the extent of hydrolysismay be modified by varying the extent to which the organic-"propped"species is dried prior to addition of the polymeric oxide precursor. Asnoted earlier, the product after conversion to the polymeric oxide formmay be exposed to conditions which remove the organic cation proppingagents, e.g., exposure to elevated temperature.

The amount of interspathic polymeric oxide contained within the finalproduct can be greatly varied because the polymeric oxide precursorspecies are introduced in an electrically neutral form such that theamount of interspathic material incorporated within the layered oxide isnot dependent upon the charge density of the original layered oxide.This allows the formation of materials with widely varying interlayerspacing, which permits accommodation of metal-containing moleculesthrough the layered metal oxide.

The resulting product may have d-spacings greater than 10, 15, 20, 25 oreven 30 anstroms. Layered oxides of elements ranging in atomic numberfrom 13 to 15, 21 to 33, 39 to 51, 57 to 83 and greater than 90 may beemployed as starting materials. Included among these materials areKTiTaO₅, and Na₄ Mn₁₄ O₂₇.9H₂ O, as well as oxides of aluminum andsilicon such as clays. Layered clays such as bentonite or layeredsilicates, for example, the metasilicates magadiite, natrosilite,kenyaite, maketite and kauemite, may be utilized as starting materialsfor the layered materials used in the present invention. It has beenfound preferable, or in some cases, necessary that these layered claysor silicates be treated by contacting with one or more polar solventsprior to or during exchange with the source of organic cation. The polarsolvent used should exhibit electric dipole moments in the gas phase ofat least 3.0 Debeyes (D), preferably at least 3.5 Debeyes, say at leastabout 3.8D. Examples of suitable solvents are dimethylsulfoxide (DMSO)and dimethylformamide (DMF). The intercalation of synthetic magadiitewith organic liquids such as DMSO, followed by treatment withalkylamines is discussed in American Mineralogist, Volume 60, pages650-658, 1975, incorporated herein by reference. It is believed that thetreatment of any starting material with one or more highly polarsolvents can be useful in facilitating the introduction of the source oforganic cation between the layers of starting material.

The layered metal oxide component used in the present invention may beprepared from starting materials such as layered oxides of Gr. IV Ametals such as titanium, zirconium and hafnium. In particular, layeredtitanates, e.g., trititanates like Na₂ Ti₃ O₇ are useful startingmaterials. The starting materials comprise an interspathic cationicspecies between their layers. Trititanate is a commercially availablematerial whose structure consists of infinite anionic sheets of titaniumoctahedra with intercalated alkali metal cations. The layered metaloxide component contains a stable polymeric oxide, preferably silica,between adjoining layers resulting in a heat-stable material whichsubstantially retains its interlayer distance upon calcination.Silicotitanates employed in the present invention exhibit thecharacteristic x-ray diffraction pattern of Table 1 below.

                  TABLE 1                                                         ______________________________________                                        Composite List of Principal X-Ray Powder*                                     Diffraction Peaks For Silicotitanates                                         Line    2 Theta-2 Theta                                                                             100 I/I.sub.o                                           Number  Minimum Maximum                                                                             (Relative Intensity) Range                              ______________________________________                                        1       less than     VS to W                                                         or equal to 8.7                                                       2       11.1-14.3     S to W                                                  3       11.8-15.2     M to W                                                  4       24.5-25.0     VS to W                                                 5       25.0-25.4     M to W                                                  6       28.5-30.2     VS to W                                                 7       29.8-30.6     S to W                                                  8       33.0-33.5     S to W                                                  9       43.2-43.5     M to W                                                  10      44.2-44.7     M to W                                                  11      48.5-48.9     VS to M                                                 12      52.7-52.9     W                                                       ______________________________________                                         *2 Theta minimum-2 Theta maximum = Range of 2 Thetavalues observed for        eight specific pillared silicotitanates                                  

These values were determined by standard techniques. The radiation wasthe K-alpha doublet of copper, and a scintillation counter spectrometerwas used. The peak heights, I, and the positions as a function of 2times theta, where theta is the Bragg angle, were determined. Fromthese, the relative intensities, I/I_(o) where I_(o) is the intensity ofthe strongest line or peak, and d is the interplanar spacing inangstroms (A), corresponding to the recorded lines, were calculated. Therelative intensity in the table above is expressed as follows:

    ______________________________________                                        Relative Intensity                                                                             100 I/I.sub.o                                                ______________________________________                                        VS (Very Strong)  60-100                                                      S (Strong)       40-60                                                        M (Medium)       20-40                                                        W (Weak)          0-20                                                        ______________________________________                                    

Variations in the interplanar spacing and relative intensity may occuras a result of ion exchange, changes in the composition of thesilicotitanate, or exposure to calcination conditions.

The interspathic polymeric oxides formed between the layers of thelayered oxide components of the present invention are preferably oxidesof elements selected from Group IV B of the Periodic Table, includingsilicon, germanium, tin and lead, with silicon especially preferred. Thepolymeric oxide precursor may be an electrically neutral, hydrolyzablecompound, such as tetrapropylorthosilicate, tetramethylorthosilicate, orpreferably tetraethylorthosilicate. In addition, the polymeric oxideprecursor may contain zeolite precursors such that exposure toconversion conditions results in the formation of interspathic zeolitematerial as at least some of the polymeric oxide.

The starting layered oxide material is treated with an organic compoundcapable of forming cationic species such as organophosphonium ororganoammonium ion, before adding the polymeric oxide source. Insertionof the organic cation between the adjoining layers serves to separatethe layers in such a way as to make the layered oxide receptive to theinterlayer addition of the electrically neutral, hydrolyzable, polymericoxide precursor. In particular, alkylammonium cations have been founduseful in the present invention. C₃ and larger alkylammonium, e.g.,n-octylammonium, is readily incorporated within the interlayer speciesof the layered oxides, serving to prop open the layers in such a way asto admit the polymeric oxide precursors. The extent of the interlayerspacing can be controlled by the size of the organoammonium ionemployed. Indeed, the size and shape of the ammonium ion can affectwhether or not the organoammonium ion can be interspathicallyincorporated within the layered oxide structure at all. For example,bulky cations such as tetrapropylammonium are not particularly suited tothe present invention.

The organic ammonium cation precursor may be formed by combining aprecursor amine and a suitable acid, e.g. mineral acids such ashydrochloric acid. The layered oxide starting material can then becombined with the resulting aqueous solution of ammonium ion to form alayered oxide containing intercalated organic material and water. Theresulting "propped" product is then contacted with an electricallynetural, hydrolyzable polymeric oxide precursor. After hydrolysis,preferably by exposure to interspathic water, the polymeric oxideprecursor forms a thermally stable polymeric oxide. A final calcinationstep may be employed which is severe enough to remove the organicinterspathic species. Remaining organic may also be removed, if desired,by a separate chemical treatment.

Layered metal oxides containing an interspathic polymeric oxide such asthose described above have now been found to be useful in upgradingresidual oil, particularly in demetallation by hydrotreating. Thelayered materials useful in the method of the present inventionpreferably exhibit significant interlayer separation and possess ad-spacing of at least about 10 angstroms. The interspathic polymericoxide serves to adequately maintain the interlayer separation even atthe conditions of temperature and pressure encountered during residupgrading. The layered metal oxides described above are particularlyuseful in resid upgrading catalysts because their layered structureresults in pores which are relatively long and narrow. Such pore shapesare believed to readily accommodate all or part of the large planarmetal complexes found in asphaltene portions of resid and thus permitaccess of such metal complexes to catalytic sites within the catalysts.

The present invention relates to a method for hydrotreating 350° C.⁺ andpreferably 540° C.⁺ residual oil which comprises utilizing ahydrotreating catalyst which contains a thermally stable compositioncomprising a layered metal oxide containing an interspathic polymericoxide having a d-spacing of at least about 10 angstroms, 15 angstroms,or 20 angstroms under hydrotreating conditions.

The present invention may also relate to a method for removing metalfrom a metal-containing residual oil by hydrotreating. The residual oilis contacted with hydrogen in the presence of a hydrotreating catalystcomprising a layered metal oxide containing an interspathic polymericoxide having a d-spacing of at least about 10 angstroms. Preferably, thehydrotreating catalyst contains a metal selected from the groupconsisting of group VIB and Group VIII metals. Preferably, thehydrotreating catalyst comprises a layered silicotitanate. The metalsremoved from the residual oil may include such common crude oil metalcontaminants as nickel, vanadium, iron, copper, zinc and sodium, and areoften in the form of large organometallic complexes such as metalporphyrins or asphaltenes.

The residual feedstock employed in the present invention will normallybe substantially composed of residual hydrocarbons boiling above 340° C.and containing a substantial quantity of asphaltic materials. Thus thechargestock can be one having an initial or 5 percent boiling pointsomewhat below 340° C. provided that a substantial proportion, forexample, about 70 or 80 percent by volume, of its hydrocarbon componentsboil above 340° C. A hydrocarbon stock having a 50 percent boiling pointof about 480° C. and which contains asphaltic materials, 4 percent byweight sulfur and 50 p.p.m. nickel and vanadium is illustrative of suchchargestock.

The process of the present invention may be carried out by contacting ametal and/or sulfur contaminated feedstock with the above-describedhydrotreating catalyst under hydrogen pressures of at least about 2860kPa (400 psig), temperatures ranging between about 357° to 454° C. (675°to 850° F.) and liquid hourly space velocities between about 0.1 and 10hr⁻¹. Preferably these conditions include hydrogen pressures betweenabout 7000 to 17000 kPa (about 1000 to 2500 psig), temperatures betweenabout 370° to 440° C. (about 700° to 825° F.), and liquid hourly spacevelocities between about 0.2 and 1.0 hr⁻¹.

The catalytic hydrotreating may take place in any suitable hydrotreatingreactor, preferably a fixed bed downflow (trickle bed) reactor. Othersuitable hydrotreaters include moving bed downflow ("bunker") reactors,fluidized bed or ebullated bed reactors and fixed bed upflow reactors.

The use of the present hydrotreating catalysts in resid upgrading isparticularly desirable because they exhibit greater activity,particularly in metals removal. Accordingly a refiner can attain therequired degree of metals removal with less catalyst in a smallerreactor. In view of the high pressures required for hydroprocessingresids, it is highly desirable from an economic standpoint to utilize areactor of the smallest size allowable. Alternatively, hydrotreatingwith the catalysts of the present method in larger reactors allows arefiner to operate at lower reaction severities or to attainhydrotreated resids of improved quality. In view of this, the method ofthe present invention is believed particularly useful in pretreating FCCfeed or producing metallurgical grade coke.

The following examples are given to further describe the presentinvention.

EXAMPLE 1 Preparation of Reference CoMo/Al₂ O₃, Catalyst A

The support for reference catalyst A was prepared by extruding a mixtureof water and alpha alumina monohydrate ("Catapal SB") to 1/32"extrudate, drying at about 140° C., and calcining at a particulartemperature to give a distinct pore size distribution. The calcinedextrudate was then sequentially impregnated via the incipient wetnesstechnique with ammonium heptamolybdate and cobalt chloride. Drying atabout 140° C. and calcination at 540° C. followed each of the twoimpregnations. Properties of the resultant Catalyst A are shown in Table2.

                  TABLE 2                                                         ______________________________________                                        CoMo/Al.sub.2 O.sub.3 Resid Demetalation Catalyst Properties                  ______________________________________                                        Metals Loading (wt %)                                                         CoO                3.5                                                        MoO.sub.3          10.0                                                       Physical Properties                                                           Surface Area, m.sup.2 /g                                                                         109                                                        Real Density, g/cc 3.629                                                      Particle Density, g/cc                                                                           1.221                                                      Pore Volume, cc/g  0.543                                                      Avg. Pore Dia., Ang.                                                                             199                                                        PSD, % PV in Pores of                                                          0-30 Ang. Diameter                                                                              11                                                          30-50             --                                                          50-80             --                                                          80-100            2                                                          100-150            24                                                         150-200            34                                                         200-300            17                                                         300+               12                                                         ______________________________________                                    

EXAMPLE 2 Preparation of H₂ Ti₃ O₇

Acid titanate, H₂ Ti₃ O₇, was prepared from exchange of Na in Na₂ Ti₃ O₇with 1M HCl in triplicate as described: 780.7g 37.4% HCl was diluted to8 liters total volume with water in a 12 liter 4-necked round bottomflask equipped with a mechanical stirrer, reflux condenser, andthermometer. 500 Grams of Na₂ Ti₃ O₇ were added, and the resultingmixture was heated with stirring at 75°-80° C. for 24 hours. Thesolution was then filtered and washed with 2 liters of hot water. Theprocedure was repeated in triplicate. After the third exchange, theproduct was washed with hot water until chloride free. The product afterdrying in vacuo at 77° C. had an X-ray diffraction pattern similar tothat reported for H₂ Ti₃ O₇ by H. Izawa, S. Kikkaw, and M. Kolzumi, J.Phys. Chem., 86,5023 (1982) and the following composition (wt %).

TiO₂, 93.4

Na, 0.28

EXAMPLE 3 Preparation of Silicotitanate

Concentrated HCl (315.6 g of 37.2% HCl) was dissolved in 700 g water,and the resulting solution was stirred and cooled in an ice bath.n-Octylamine (427.1 g) was added portionwise, keeping the solution below50° C. 100 l grams of Na₂ Ti₃ O₇ was added, and the mixture wastransferred to a 2 liter polypropylene jar and heated at 100° C. withoccasional stirring for 24 hours. The mixture was filtered, washed with5 liters hot water, and dried at room temperature for 24 hours. Aportion of this dried product (90 g) was stirred in 600 gtetraethylosthiosilicate for 72 hours at room temperature, filtered, anddried at room temperature for 24 hours. This product was calcined at1000° F. in nitrogen for one hour and in air for 2 hours. The propertiesof this silicotitanate product are provided in Table 3.

                  TABLE 3                                                         ______________________________________                                        Properties of Catalyst A Silicotitanate of Example 3                          ______________________________________                                        SiO.sub.2 /TiO.sub.2, molar                                                                     0.52                                                        Na, wt %          2.80                                                        Ash, wt %         98.45                                                       Surface Area, m.sup.2 /g                                                                        225.00                                                      Sorption, wt %                                                                H.sub.2 O         10.6                                                        Cyclohexane       7.6                                                         n-Hexane          6.1                                                         ______________________________________                                    

EXAMPLE 4 Preparation of Molybdenum-Containing Titanate, Catalyst B

A Mo/Na₂ Ti₃ O₇ material was prepared by the conventional incipientwetness technique on sodium titanate using ammonium heptamolybdate.Following impreganation to 10 wt % MoO₃, the material was calcined inair at 800° F. for 3 hours. The resultant catalyst was identified asCatalyst B.

EXAMPLE 5 Preparation of Molybdenum-Containing Titanate, Catalyst C

Using the acid titanate produced from Example 2, a Mo impregnation andcalcination similar to Example 4 were completed. The finished materialwas identified as Catalyst C.

EXAMPLE 6 Preparation of Molybdenum-Containing Titanate, Catalyst D

Using the silicotitanate of Example 3, a Mo impregnation and calcinationsimilar to Examples 4 and 5 were completed. The finished material wasidentified as Catalyst D.

Properties of Catalysts B, C, and D are set out in Table 4.

                                      TABLE 4                                     __________________________________________________________________________    Properties of Molybdenum-Containing Titanate Catalysts                                    Catalyst B                                                                             Catalyst C                                                                             Catalyst D                                                  Mo-Impregnated                                                                         Mo-Impregnated                                                                         Mo-Impregnated                                  __________________________________________________________________________    Form        Na.sub.2 Ti.sub.3 O.sub.7                                                              H.sub.2 Ti.sub.3 O.sub.7                                                               Silicotitanate                                              8/20 Mesh                                                                              8/20 Mesh                                                                              8/20 Mesh                                                   Particles                                                                              Particles                                                                              Particles                                       Density, g/cc                                                                 Packed      0.57     0.54     0.59                                            Pore Volume cc/g                                                                          NA       NA       0.497                                           Surface Area M.sup.2 /g                                                                   5        5        45                                              Avg. Pore   NA       NA       442                                             Diameter, Ang.                                                                % Pore Volume in Pores of Varying Diameters (angstroms)                        0-30 Ang. Diameter                                                            30-50 Ang. Diameter          1                                                50-80 Ang. Diameter          1                                                80-100 Ang. Diameter         2                                               100-150 Ang. Diameter         3                                               150-200 Ang. Diameter         2                                               200-300 Ang. Diameter         3                                               300+ Ang. Diameter            87                                              __________________________________________________________________________

EXAMPLE 7 Shaker Bomb Testing of Catalysts of A, B, C & D Using ArabLight Vacuum Resid

The catalysts of Examples 1, 4, 5 and 6 all crushed and sized to a logmeans particle diameter of 14 to 20 Mesh (Tyler) were employed inhydrotreating an Arabian Light vacuum resid (540° C.⁺ boiling range)described in Table 5 in a shaker bomb apparatus (see J. W. Payne, C. W.Streed and E. R. Kent, "The Shaker Bomb - A New Laboratory Tool forStudying Thermal Processes", Ind. Eng. Chem., 50 (1), 47 (1958)) whichapproximates resid upgrading activities observed in continuous downflowunits.

                  TABLE 5                                                         ______________________________________                                        Arabian Light Vacuum Resid Feedstock                                          ______________________________________                                        Elemental Analysis (wt %)                                                     Hydrogen            10.68                                                     Sulfur              3.93                                                      Nitrogen            0.31                                                      CCR                 16.96                                                     Asphaltenes (n-C.sub.5)                                                                           10.93                                                     Metals Analysis (ppm)                                                         Nickel              16                                                        Vanadium            65                                                        Iron                12                                                        Sodium              6                                                         Kinematic Viscosity (cs)                                                      212° F.      496.2                                                     300° F.      24.6                                                      ______________________________________                                    

In a series of runs, the titanate catalysts were contacted with theresid at the following conditions:

    ______________________________________                                        Oil:Catalyst (Wt:Wt)                                                                            20                                                          Temperature, °C.                                                                         400                                                         H.sub.2 Pressure, kPa                                                                           13,890                                                      Reaction Time, min                                                                              80                                                          ______________________________________                                    

At the conclusion of each run, the catalyst and the oil were separatedand both components were analyzed. The effectiveness of each catalystfor resid upgrading was determined by comparing the degree ofdemetalation, desulfurization, CCR removal, and denitrogenation to thatobserved in an identical run in which a conventional CoMo/Al₂ O₃catalyst was used. Thermal contributions were determined from a "blank"run at identical conditions but with no catalyst present.

Table 6 presents the results of this catalyst activity comparison andshows that the molybdenum-impregnated silicotitanate catalyst wassuperior to the analogously treated sodium titanate and hydrogentitanate, catalysts with respect to CCR, vanadium, and asphaltenesremoval. Sulfur removal by all three titanate catalysts was minimal.This was expected since unpromoted MoO₃ is known to have littledesulfurization activity. Nickel levels in the sodium and hydrogentitanate treated products actually increased due to contamination thatcan be traced to the stainless steel walls of the shaker bomb. Thedemetalation activity of the silicotitanate was sufficient to take upthis additional nickel.

                                      TABLE 6                                     __________________________________________________________________________    Comparison of Resid Upgrading Catalyst Performance                                                  Catalyst B                                                                           Catalyst C                                                                            Catalyst D                                               Catalyst A                                                                          (Mo/Sodium                                                                           (Mo/Hydrogen                                                                          (Mo/Silico                                          Thermal                                                                            (CoMo/Al)                                                                           Titanate)                                                                            Titanate)                                                                             Titanate)                                __________________________________________________________________________    Conditions                                                                    Temp, °C.                                                                           400                                                              Pressure, kPa                                                                            13,890                                                             Oil/Cat (wt %)                                                                           Inf. 20                                                            Time, min     80                                                              Conversion                                                                    to 540° C.-,                                                                      13.0 32.7  4.0    17.0    24.0                                     wt %                                                                          Total Liquid Product                                                          Analysis, wt %                                                                Hydrogen   10.58                                                                              10.88 10.24  10.26   10.22                                    Sulfur     3.47 2.52  3.96   3.87    3.87                                     Nitrogen   0.32 0.26  0.26   0.26    0.26                                     Vanadium, ppm                                                                            70   33    62     62      24                                       Nickel, ppm                                                                              16   10    18     19      12                                       CCR, wt %  16.00                                                                              14.44 16.46  16.04   16.37                                    Asphaltenes wt %                                                                         8.52 5.40  6.99   9.76    5.56                                     Removal, %                                                                    Vanadium   0    49    5      5       63                                       CCR        6    15    3      6       3                                        Sulfur     12   36    0      2       2                                        Asphaltenes                                                                              22   51    36     11      49                                       __________________________________________________________________________

Compared to the conventional CoMo/Al₂ O₃ catalyst, Mo/silicotitanate hasgreater demetalation activity (63 percent vs. 49 percent). Asphalteneremoval activities of the two catalysts are virtually equivalent (49percent vs 51 percent).

It is claimed:
 1. A method for hydrotreating residual oil whichcomprises contacting said oil with a hydrotreating catalyst whichcontains a thermally stable composition comprising a layered metal oxidecontaining an interspathic polymeric oxide having a d-spacing of atleast about 10 angstroms at hydrotreating conditions which include atemperature ranging from about 357° to 454° C. (675° F. to 850° F.), ahydrogen partial pressure of at least about 2860 kPa (400 psig) and aliquid hourly space velocity ranging between about 0.1 and 10 hr⁻¹,wherein said layered metal oxide is a layered silicate selected from thegroup consisting of magadiite, natrosilite, kenyaite, makatite andkanemite.
 2. The method of claim 1 wherein said hydrotreating catalystcontains a Group VIB metal selected from the group consisting ofchromium, molybdenum and tungsten.
 3. The method of claim 2 wherein saidhydrotreating catalyst contains a Group VIII metal.
 4. The method ofclaim 3 wherein said Group VIII metal is selected from the groupconsisting of iron, cobalt, nickel, palladium and platinum.
 5. Themethod of claim 1 wherein said d-spacing is at least about 15 angstroms.6. The method of claim 5 wherein said d-spacing is at least about 20angstroms.
 7. The method of claim 1 wherein said hydrotreating occurs ina fixed bed downflow reactor.
 8. The method of claim 1 wherein saidhydrotreating catalyst contains molybdenum.
 9. The method of claim 1wherein said hydrotreating catalyst contains cobalt.
 10. The method ofclaim 1 wherein said hydrotreating catalyst contains molybdenum andcobalt.
 11. The method of claim 1 wherein said hydrotreating catalystcontains nickel.
 12. The method of claim 1 wherein said hydrotreatingcatalyst contains tungsten.
 13. The method of claim 1 wherein saidhydrotreating catalyst contains nickel and tungsten.
 14. The method ofclaim 1 wherein said hydrotreating conditions include a temperatureranging from about 370° C. to 440° C. (700° F. to 825° F.), a hydrogenpartial pressure ranging from about 7000 to 17,000 kPa (1000 to 2500psig), and a liquid hourly space velocity ranging between about 0.2 to1.0.
 15. A method for removing metal from a metal-containing residualoil which comprises hydrotreating said residual oil with a hydrotreatingcatalyst comprising a layered silicate containing an interspathicpolymeric oxide selected from the group consisting of magadiite,natrosilite, kenyaite, makatite and kanemite, and having a d-spacing ofat least about 15 angstroms wherein said catalyst contains a Group VIBmetal at a temperature ranging from about 357° C. to 454° C. (675° F. to850° F.), a hydrogen partial pressure of at least about 2860 kPa (400psig) and a liquid hourly space velocity ranging between about 0.1 and10 hr⁻¹.
 16. The method of claim 15 wherein said metal removed isvanadium.
 17. The method of claim 15 wherein said metal removed isnickel.
 18. The method of claim 1 wherein said layered silicate ismagadiite.
 19. The method of claim 14 wherein said layered silicate ismagadiite.